Proposed projects include: 1) Raising monoclonal antibodies against human and hamster fibroblast and plasma fibronectins. 2) Investigating the role of fibronectin as an adhesive molecule for pulmonary endothelial and alveolar epithelial type II cells using domain specific fibronectin antibodies and defined fragments of fibronectin. 3) Studying the role of fibronectin in organization of the extracellular matrix synthesized by fibroblasts using antibodies specific for the gelatin binding domain of fibronectin. 4) Investigating the morphological and biochemical alterations in endothelial cell fibronectin during migration of polymorphonuclear leukocytes through confluent monolayers of endothelial cells. 5) Investigate the physiologic function of human alveolar macrophage fibronectin.